@juiceme, that might explain the coupling between the entertainment system and the engine control. So far so good. I can understand that and hide it under the umbrella of accidental side effect that I mentioned in my post.

What I do not understand is why any of those has to be coupled to any kind of radio. That is an additional feature that turns a gun you can use to shoot yourself in the foot into a gun that anyone can use to shoot your brains out.